This earlyEarly this morning, I took a walk outside my community, and saw many crops I used to see when I was a child in my village.

Swapped "early" with "this", it sounds more natural.

As far as I can remember, owners of large farmland planted wheat, sweet potatoes, cotton, sorghum, soybean and corn, and small pieces ofowners of smaller farmlands planted other crops.

I changed "large farmland" to "owners of large farmland" because you used a verb "planted" which needs a noun, and the farms don't plant themselves (did something similar with "small farmland")

After farmers harvested wheat, the first thing they shwould do was pay taxes using the wheat.

If you're talking about something that happened in the past, you want to use 'would'. 'Should' refers to what they ought to do in the future.

Coupled with theThere was a low yield because of the backward agricultural technology, a. Although the villagers planted wheat, we were hardly able to eat wheat, butit and instead ate only sweet potatoes.

Not sure what "coupled with" was trying to say. I broke into separate sentences for clarity. Also "We were hardly able to eat it (it refers to wheat) and instead (in place of wheat) ate sweet potatoes".

The villagers used cotton to make clothes and used soybeans or rapeseed to make oil for their daily lives.

I think this is what you meant?

Anyway, things have changed a lot nowadays.

"Anyway" is kind of a casual or informal transition for a written essay although it would work in a conversation.

But for some reason, they no longer plant cotton or sorghum any more.

"anymore" is one word

This earlyEarly this morning, I took a walk outside my community, and saw many crops I used to see in my village back when I was a child in my village.

As far as I can remember, the larger farmlands planted wheat, sweet potatoes, cotton, sorghum, soybean and corn,; and small pieces ofer farmlands planted other crops.

If you need to set a list made with commas apart from something else using a comma, that separating comma turns into a semicolon.

After the farmers harvested their wheat, the first thing they should dodid was pay their taxes using theat wheat.

CThat coupled with the low yield because of the backward agricultural technology, meant that although the villagers planted wheat, we were hardly able to eat wheat, but onlyany and instead ate sweet potatoes.

But fFor some reason, though, they no longer plant cotton or sorghum any more.

“No longer” and “any more” serve the same function, so I removed one of them.